Installing a septic tank

Rather than waste time and money connecting your rural home to the local sewage systems, why not install a septic tank? They work in most areas of the UK countryside and can last a lifetime.

There are many types of septic tank system

Living in the middle of nowhere has a number of obvious advantages, from the fresher air to the peace and quiet of the natural outdoors. There are, however, certain drawbacks; including the excessive cost and time it will take to have your new home fully fitted to all the local pipes and drainage provided by the Government. If you’re looking for a simpler solution, a septic tank, or On-Site Sewage Facility (OSFF) is the perfect alternative. Designed as small-scale sewage treatment systems, they provide rural or suburban homes with a clean and easy way of decomposing human and household waste products.

Septic tanks usually store between 1-2000 gallons of liquid waste that enters through an inlet pipe; the tank waits for solids to settle and scum to float and then anaerobically digests and reduces the volume of the solids. The remaining liquid then flows into a second chamber and is eventually drained into a neighbouring drainage or leach-field. The remaining impurities are then eliminated in the soil through various processes of transpiration and evaporation. Modern equipment is fully designed to prevent water and soil pollution and usually requires minimal maintenance on your part. There are also a variety of septic tank systems to choose from:

Types of septic tank systems:

• Gravitational system – this is the most common method for a septic tank system and works best in areas of flat ground and dry soil. A series of gravel based trenches are installed in the drainage field, below the outlet level of an ordinary septic tank. The waste effluent from the tank simply flows into the trenches and begins percolating into the soil. The number of trenches required will depend on the size of your tank and field, which vary according to the size of your house.
• Pressure distribution system – where the topography of an area doesn’t allow for a trench system to be installed in the leach-field below the tank’s outlet level, a pressure distribution system is the preferred alternative. It works on a dosing and resting cycle, with a lift-pump fitted to hold waste water until enough has been accumulated to drain the entire field – allowing maximum and even distribution of the effluent.
• Aerobic treatment unit – if the soil in your area lacks enough oxygen (such as clay-based soil) an aerobic treatment unit is ideal. It is basically a septic tank that allows extra air (primarily oxygen) to be injected into and mix with the waste water. The air allows bacteria to grow and more solids to be properly digested – the effluent being considerably cleaner on leaving the tank than in a conventional system.
• Mound system– sometimes soil is too shallow for the waste effluent to be sufficiently recycled. A mound system solves this dilemma by placing the septic system above ground level. A gravel bed containing sand fill material receives the water waste by use of a pump, which controls the dosage amount so the mound never overflows. The waste is then treated through the sand and gravel and eventually filters into the soil below.
• Sand filter system – where soil is too thin to properly breakdown the waste water the septic tank and drainage field can be separated by a layer of sand – the water leaving the tank is therefore exposed to a kind of pre-treatment before reaching the leach-field, making sure the elements are properly broken down.
• Imhoff tank – this is basically a septic tank with an additional fitted third section that collects all the undigested solids in a lower chamber – allowing sedimentation of the incoming water waste on the upper level to be purer and less prone to infiltration. This will prevent clogging of pipes but does involve cleaning out the lower section every six months to a year.

Once you’ve chosen the right septic tank system for your location and soil type, it is important to remember that the equipment must be well looked after and properly maintained to keep things running smoothly and avoid costly repairs later on. Dumping waste products such as oil, or non-biodegradable items such as cigarette butts or cotton buds into the systems can block pipes and damage the plastic or fibreglass interior. Along with pesticides and other household chemicals, oil can also produce a strong, unpleasant odour that is difficult to eliminate once in the system. Before installation, tree roots should also be cleared in the desired area to prevent damage or rupture to the tank.

Cost of installing a septic tank

There are also a number of extras to think about to make your septic tank last longer. Deep, cylindrical seepage pits in the middle of leach-fields allow for extra and more expansive perforation, as do additional siphoning pipes to increase the volume and velocity of outflow. A drip-irrigation system also prevents over saturation of the drainage field, while nitrogen-reducing technologyin the tank can help prevent algae build-up and mean less cleaning for you! Before hiring a professional installer check with your Local Authority whether you will need a planning permit, and shop around to find the best value for you. The tank itself can cost as little as £350, while a completely new system can be fitted for around £2000. As long as your septic tank is properly designed and installed, it should last you decades to come.